On the Lagrangian structure of 3D consistent systems of asymmetric quad-equations

Recently, the first-named author gave a classification of 3D consistent 6-tuples of quad-equations with the tetrahedron property; several novel asymmetric 6-tuples have been found. Due to 3D consistency, these 6-tuples can be extended to discrete integrable systems on Z^m. We establish Lagrangian structures and flip-invariance of the action functional for the class of discrete integrable systems involving equations for which some of the biquadratics are non-degenerate and some are degenerate. This class covers, among others, some of the above mentioned novel systems.Comment: 21 pp, pdfLaTe

Cartography for Communities: An Examination of Participatory Action Mapping

Participatory Action Mapping (PAM) as a methodology strives to fill the gaps created by participatory and critical mapping methodologies. Public participatory GIS (PPGIS), which often fails to elicit a bottom up approach to mapping, and community mapping, which typically produces critical mappings that often fail to be taken seriously by decision makers both fall short in offering members of the public meaningful opportunities to make claims about particular places. Through the implementation of a critical mapping methodology that utilizes professional cartography techniques, PAM offers community organizations the ability to assert their claims through maps. Using a critical cartography lens, this case study focuses on PAM with a community-based organization in west Atlanta and reveals how this methodology can be successful in engaging professional mapping practices to communicate the truths of, and subsequently inspire action among, community members

Studies of fiber-matrix adhesion on compression strength

A study was initiated on the effect of the matrix polymer and the fiber matrix bond strength of carbon fiber polymer matrix composites. The work includes tests with micro-composites, single ply composites, laminates, and multi-axial loaded cylinders. The results obtained thus far indicate that weak fiber-matrix adhesion dramatically reduces 0 degree compression strength. Evidence is also presented that the flaws in the carbon fiber that govern compression strength differ from those that determine fiber tensile strength. Examination of post-failure damage in the single ply tests indicates kink banding at the crack tip

Blind Normalization of Speech From Different Channels

We show how to construct a channel-independent representation of speech that has propagated through a noisy reverberant channel. This is done by blindly rescaling the cepstral time series by a non-linear function, with the form of this scale function being determined by previously encountered cepstra from that channel. The rescaled form of the time series is an invariant property of it in the following sense: it is unaffected if the time series is transformed by any time-independent invertible distortion. Because a linear channel with stationary noise and impulse response transforms cepstra in this way, the new technique can be used to remove the channel dependence of a cepstral time series. In experiments, the method achieved greater channel-independence than cepstral mean normalization, and it was comparable to the combination of cepstral mean normalization and spectral subtraction, despite the fact that no measurements of channel noise or reverberations were required (unlike spectral subtraction).Comment: 25 pages, 7 figure

Venus High Temperature Atmospheric Dropsonde and Extreme-Environment Seismometer (HADES)

The atmospheric composition and geologic structure of Venus have been identified by the US National Research Council's Decadal Survey for Planetary Science as priority targets for scientific exploration, however the high temperature and pressure at the surface, along with the highly corrosive chemistry of the Venus atmosphere, present significant obstacles to spacecraft design that have severely limited past and proposed landed missions. Following the methodology of the NASA Innovative Advanced Concepts (NIAC) proposal regime and the Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) design protocol, this paper presents a conceptual study and initial feasibility analysis for a Discovery-class Venus lander capable of an extended-duration mission at ambient temperature and pressure, incorporating emerging technologies within the field of high temperature electronics in combination with novel configurations of proven, high Technology Readiness Level (TRL) systems. Radioisotope Thermal Power (RTG) systems and silicon carbide (SiC) communications and data handling are examined in detail, and various high-temperature instruments are proposed, including a seismometer and an advanced photodiode imager. The study combines this technological analysis with proposals for a descent instrument package and a relay orbiter to demonstrate the viability of an integrated atmospheric and in-situ geologic exploratory mission that differs from previous proposals by greatly reducing the mass, power requirements, and cost, while achieving important scientific goals

High temperature strength retention of Cu/Nb nanolaminates through dynamic strain ageing

The mechanical properties of Cu/Nb metallic nanolaminates with different layer thickness (7, 16, 34 and 63 nm) were studied by means of micropillar compression tests from room temperature to 400 C. Both strain-rate jump and constant strain rate tests were carried out and they showed evidence of dynamic strain ageing in the nanolaminates with 7, 16 and 34 nm layer thickness deformed at 200 C. Dynamic strain ageing was accompanied by a reduction of the strain rate sensitivity to 0, high strength retention at 200 C and the development of shear localization of the deformation at low strains (5%-6%) that took place along the Nb layers in the nanolaminates. Atom probe tomography of the deformed specimens revealed the presence of O in solid solution in the Nb layers but not in the Cu layers. Thus, diffusion of O atoms to the mobile dislocations in Nb was found to be the origin of the dynamic strain ageing in the Cu/Nb nanolaminates around 200 C. This mechanism was not found at higher temperatures (400 C) because deformation was mainly controlled by stress-assisted diffusion in the Cu layers. This discovery shows a novel strategy to enhance the strength retention at high temperature of metallic nanolaminates through dynamic strain ageing of one the phases

Thermoelectric and structural properties of transparent Sb-Doped ZnO thin films sputtered in a confocal geometry

This study focuses on understanding the influence of low Sb doping on ZnO’s electrical, optical, and thermoelectrical properties, while also studying its structural and morphological parameters. For this, several ZnO films with varying Sb target current densities, in the range of 0–0.27 mA/cm2, were produced by DC magnetron sputtering in a confocal geometry. As a result, thin ZnO:Sb films with an average transparency in the visible region greater than 80% are obtained, revealing for optimized conditions an absolute Seebeck coefficient of 100 µV/K and a respective power factor of 1.1 mW·m−1·K−2 at 300 K, effectively modifying the electrical, optical, and thermoelectrical properties of the material and ensuring its suitability for heat harvesting applications. From atom probe tomography experiments, a larger Zn content is registered at triple junctions of the grain boundary, which matches the approximately 25 nm crystallite grain size derived from the X-ray diffraction analysis.This research is funded by FCT/PIDDAC through the Strategic Funds project reference UIDB/04650/2020-2023. Joana M. Ribeiro is grateful to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for the Ph.D grant SFRH/BD/147221/2019. This work (proposal ID 2021-025-030112) was carried out with the support of the Karlsruhe Nano Micro Facility (KNMFi, www.knmf.kit.edu, accessed on 8 March 2023), a Helmholtz Research Infrastructure at Karlsruhe Institute of Technology (KIT, www.kit.edu, accessed on 8 March 2023)

Services surround you:physical-virtual linkage with contextual bookmarks

Our daily life is pervaded by digital information and devices, not least the common mobile phone. However, a seamless connection between our physical world, such as a movie trailer on a screen in the main rail station and its digital counterparts, such as an online ticket service, remains difficult. In this paper, we present contextual bookmarks that enable users to capture information of interest with a mobile camera phone. Depending on the user’s context, the snapshot is mapped to a digital service such as ordering tickets for a movie theater close by or a link to the upcoming movie’s Web page

Vorhersage des räumlichen Auftretens von Schadstoffen in Überschwemmungsgebieten mittels morphologischer und hydrologischer Parameter von Flussauen

Ziel eines laufenden UFOPLAN-Projektes ist die Weiterentwicklung einer Methode zur Kennzeichnung des stofflichen Zustands von Auenböden für Flüsse 1. und 2. Ordnung für einen bundesweiten Kartenmaßstab. Bislang wurden als wichtige Einflussfaktoren im Geodaten identifiziert, die auf die Herkunft von Schadstoffen aus natürlichen und anthropogenen Quellen fokussieren (z.B. Landnutzung, Rezente oder Altlaue, Einfluss von Bergbau, Einwohnerdichte, Lithologie, das Flussgebiet selbst, Eigenschaften der Einzugsgebiete von Zuflüssen). Auf Grundlage dieser Daten wurden bereits Raumeinheiten abgeleitet, die jeweils für spezifische Stoffmuster und -konzentrationen repräsentativ sind. Hierfür flossen bundesweit rund 11.400 Oberbodenproben in Auen ein. Fließgewässerauen stehen jedoch im permanenten stofflichen Austausch mit ihrer Umgebung und sind durch Erosions- und Sedimentationsprozesse von der Umlagerung erheblicher Mengen an Bodenmaterial und daran gebundener Schadstoffe vor allem innerhalb der Auengebiete geprägt. Das Ausmaß dieser Transportprozesse variiert zeitlich stark und ist u. a. von der Hydrodynamik des Fließgewässers abhängig. Da sich sowohl organische Schadstoffe bevorzugt an Partikel wie z. B. organisches Material oder Tonminerale anlagern, ist das Schadstoffmuster und der -gehalt von Auenböden mit dem Sedimentationsverhalten eng verknüpft. Der Sedimentrückhalt ist wiederum im Wesentlichen von der Häufigkeit und Dauer der Hochwasserereignisse, der Fließgeschwindigkeit des Wassers und der Auentopografie abhängig. Aus diesen Gründen wurden geeignete morphologische und hydrologische Parameter für die Charakterisierung von Flussauen (nach Koenzen 2005) in die Methode integriert. Ziel war es zum einen, Aussagen für Auenabschnitte ohne Daten zu ermöglichen und zum anderen die Sicherheit der Vorhersage für Stoffmuster und -konzentration in Gebieten mit wenig Messpunkten signifikant zu erhöhen